The signaling is provided in signaling frames which are in turn transmitted in a data band instead of speech frames.
A data receiver—referred to for short in the following text as a “receiver”—must be able to distinguish between the signaling frames mentioned above and speech frames.
In the method according to the prior art, this distinction is made with the aid of specific identification patterns (also referred to as “markers”). A protocol for signaling is specified in conventional data transmission channels. The signaling is used, for example, for:    a) fixing different data rates;    b) switching between different data rates; and    c) DTX (discrete transmission) handling.
In general, with mixed digital transmission of speech data and other data, received data blocks must be analyzed in an appropriate receiver. In order to save computation time and in order to ensure a high transmission rate, this analysis must be carried out as efficiently and quickly as possible at the receiver end.
In order to distinguish between data blocks which transmit only speech information and are therefore referred to in the following text as speech blocks, and data blocks which transmit other data or receiver-specific information, for example the switching between different speech codes, and are thus referred to in the following text as signaling blocks, conventional receiver-end analysis systems use specific identification patterns or “markers” in order to identify signaling frames which are contained in the signaling blocks.
FIG. 4 shows a schematic flowchart of a method for recognition of identification patterns according to the prior art, in which received data blocks 201 are searched sequentially in full rate signaling blocks 206, with full rate signaling frames 208a–d being set successively for identification patterns. 401 in this case denotes a decision device for jumping back to the next full rate signaling block 206, and 103 denotes a result output step.